Transmission



June 2, 1953 JANDASEK 2,640,373

TRANSMISSION I Filed NOV. 15, 1949 4 Sheetg-Sheet l I N V EN TOR. Jase 9i Jab/6145a,}.

J. JANDASEK TRANSMISSION June 2, 1953 4 Sheets-Sheet 2 Filed Nov. 15, 1949 m MW NH i w mi WWW J. JANDASEK TRANSMISSION June 2, 1953 4 Sheets-Sheet 3 Filed Nov. 15, 1949 J. JANDASEK TRANSMISSION June 2, 1953 4 Sheets-Sheet 4 Filed Nov. 15, 1949 INVENTOR.

' irra/FVVE/i Patented June 2, 1953 T OFFICE TRANSMISSION Joseph Jandasek, Highland Park, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application November 15, 1949, Serial No. 127,455

15 Claims.

This invention relates to power transmission units of the type including a hydraulic to q converter in combination with a plurality of dr ve transmitting gear trains.

It is a primary object of this invention to provide a simplified form of highly flexible power transmission unit which unit includes a combination hydraulically and mechanically transmitted, torque multiplying, accelerating underdrive train and means for automatically converting the accelerating underdrive train into a positively connected, two-way, forward, direct drive.

It is a further object of this invention to provide in a power transmission unit of the aforedescribed type means whereby the forward direct drive may be automatically downshifted to the accelerating underdrive ratio as the speed and torque load applied to the transmission output shaft varies and to further include means whereby the direct drive may be manually downshifted to the accelerating underdrive at the will of the operator irrespective of the automatic downshift controls.

It is another object of this invention to provide in a transmission unit of the aforedescribed type means whereby the positive direct drive may be manually downshifted to the accelerating underdrive ratio so that the underdrive ratio may be used as a coasting brake as well as an accelerating gear train.

It is a further object of this invention to provide a transmission unit of the aforedescribed type with manually operable means whereby turbo-braking may be obtained in the hydraulic converter unit to assist the engine braking obtainable when the transmission unit is conditioned for transmitting direct drive.

Other objects and advantages of this invention will become readily apparent from a reading of the attached specification and a consideration of the related drawings wherein:

Fig. 1 is a partial sectional view of the hydraulic torque converter unit used in this transmission;

Fig. 2 is a sectional elevational view taken along the line 22 of Fig. 1 showing the oneway brake associated with the converter reaction member;

Fig. 3 is a sectional elevational view of the gear box used in this transmission unit;

Fig. 4 is a diagrammatic view, partly in sectional elevation, of the torque converter unit, portions of the gear box and the hydraulically operated control system for the transmission unit;

Fig. 5 is another diagrammatic view of the transmission unit and the controls therefor including the manually operated drive selector mechanism; and

Fig. 6 is a diagrammatic View of the manually operable means for obtaining turbo-braking with this transmission unit.

The invention disclosed herein is a modification of and an improvement on the power transmitting units disclosed in the copending applications of Frederic W. Slack, Serial No. 84,435, filed March 30, 1949, William L. Sheppard, Serial No. 98,493, filed June 11, 1949, and Joseph Jandasek, Serial No. 11,712, filed February 2'7, 1M8, now U. S. Patent No. 2,616,310.

Figure 1 of the drawings disclose the hydrokinetic torque converter unit A that is operatively associated with the planetary gear unit B shown in Fig. 3. Converter unit A is adapted to drivingly connect a prime mover such as a motor vehicle engine to the input of the gear type torque transmitting and torque multiplying unit B which is arranged in series with the converter unit A. The reference numeral 8 represents an end portion of a driving member, such as the engine crankshaft of a motor vehicle power unit. The shaft 8 is drivingly connected to the axially flexible drive transmitting plate Q by the screw means It. The drive transmitting plate 9 has an engine starter ring gear H fixedly mounted about its periphery. Also drivingly connected to the drive plate 9 by the bolt means I2 is the torque converter casing 13 within which are mounted the various converter components, namely, the impeller member M, the turbine or runner member [5, and the guide Wheel or reaction member The vaned impeller wheel is is fixedly connected to the converter casing 13 by welds or the like and is accordingly adapted to be rotatably driven by the driving shaft 8. The vaned turbine wheel id is drivingly connected by rivet means IQ to a radially extending flange portion it?) formed on the hub member lta that is connected by splines its to the forward end p rtion of the intermediate hollow shaft member Hi.

The intermediate shaft member 16 is adapted to transmit drive from the turbine member [5 of the torque converter unit A to the planetary gear unit B which is arranged in series with the torque converter unit A. The forward end of intermediate shaft it is journaled by its hub ita in the axially extending sleeve bearing 20 that is associated with the torque converter lockup clutch C. The rear end portion of intermediate shaft i6 is rotatably supported by a sleevetype of bearing 4| that is mounted in the fixed sleeve 32 carried by the housing 43 of the transmission unit B.

The vaned guide wheel I! is rotatably supported within the converter casing 13 by means of the guide wheel hub portion Ila, that is 1'0- tatably mounted, by means of a one-way brake device 2|, on the axially extending housing sleeve 32. Sleeve 32 is fixed to and projects from the wall 42a. of the relatively stationary, gear box bearing 42. Sleeve 32 has a hub member 32a splined thereto at 321) which hub member s pports the overrunning or one-way brake device 2|. As clearly shown in Fig. 2, the one-way brake device 2| comprises rollers Zla mounted within a cage member 211). The cage member 2!?) is normally urged into drive transmitting position by spring means not shown. Cam surfaces 320, formed on the outer peripheral surface of the sleeve hub member 32a, cooperate with the clutch rollers Zia and the outer roller race llb formed by the inner surface of the bore through the guide wheel hub member Ha. It is thought to be obvious from Fig. 2 that the one-way brake 2| will permit only forward rotary movement (clockwise when looking in the direction of arrows 2-2 of Fig. 1) to be transmitted to guide wheel I! by the forward rotation of the impeller M, the brake 2| preventing rotation of the guide wheel I! in a reverse or counterclockwise direction.

The torque converter unit A includes a gear type oil pump 25 having a driving gear 25a that is directly connected by finger means 251) to the axially extending flange portion 13b of the rotatable converter casing l3. The pump 25 draws oil from a sump 26 (see Fig. 3) and circulates it through the converter unit A, the transmission lubricating system and the various hydraulically operated control mechanisms associated with this transmission unit (see Fig. 4) The circulation of oil through the converter A, by the pump 25. provides a means for maintaining the converter full of oil whenever shaft 8 is rotating. Furthermore, this circulation of the working fluid through the converter and the lubricating and hydraulically operated control systems provides a means for cooling the converter fluid. A second pump 84, driven by the transmission output shaft 8| is also included in this transmission to provide a source of pressure fluid when the engine is not operating. This pump will be more fully described in connection with the planetary gear box B.

The relatively stationary outer housing 42 for the transmission unit has a wall portion 421) from which there projects a forwardly directed, axially extending, sleeve-like, flange portion 42a. Flange portion 420 provides a cover for the pump unit 25 and also supports a fluid seal 55 that encircles the axially extending flange l3b of the converter casing [3.

The forward portion of converter casing l3 includes the axially extending, cup-like casing seat 1311 for the bearing assembly 3| in which is rotatably mounted for forward portion of the solid drive transmitting shaft 30. Provision is made for permitting the casing seat portion l3a to expand and contract axially so as to absorb the inherent breathing tendencies of the somewhat flexible converter casing l3. Casing seat Kid is piloted within an axially extending bore 8a in the driving shaft member 8. A bearing means, such as the radially extending annular rib I30, is provided on the converter casing seat l3a and extends between the seat |3a and the inner wall of the bore 8a in driving shaft 8. This rib-like bearing formation l3c provides a sliding telescopic connection between the casing l3 and driving member 8 to accommodate the breathing tendencies of the converter casing l3. The bearing rib I30 not only provides a sliding connection between the converter casing 13 and the driving member 8 but in addition it acts as a centering means to prevent twisting or cooking of the converter unit A about its axis of rotation. This axially shiftable mounting means for the torque converter casing 13 is completely described in the co-pendin application of Augustin J. Syrovy, Serial No. 77,939, filed February 23, 1949, now U. S. Patent No. 2,588,668, and forms no part of this invention.

In order to provide means for transmitting a positive, two-way direct drive from the driving shaft 8 to the intermediate solid shaft 30 a torque converter lock-up clutch C is provided. The lock-up clutch C includes the radially extending drive transmitting disc 33 which has friction elements 33a mounted on its side faces adjacent its periphery. Drive transmitting disc 33 is drivingly connected to the solid shaft 30 through the shaft hub member 30a that is splined to the end of shaft 30 as indicated at 3012. Mounted between the disc 33. and the shaft hub member 30a are several circumferentially spaced compression spring elements 34 (only one shown) that cushion the torque impact transmitted to the disc 33 on engagement of the clutch C. Springs 34 thereby facilitate smooth engagement of the clutch C. Pins 35 are arranged to extend between the disc 33 and an anchor plate 40 through enlarged openings in the hub member 30a so as to provide an additional means to connect the disc 33 and hub member 300, in the event of failure of the springs 34. Pins 35 also urge the disc 33 and anchor plate 43 against the sides of the hub member 36a and thereby tend to damp out vibrations of the disc 33. Cooperatively associated with the drive transmitting disc 33 is a pressure fluid receiving cylinder 36 that is formed as a part of the torque converter casing 13. Mounted within the cylinder 36 is an axially shiftable, hydraulically actuated, piston 31. Cylinder 36 also supports a backing plate 38 which is arranged to cooperate with the piston 31 so as to provide a means to clampingly engage the friction faces 33a of disc 33 when pressure fluid is admitted to the cylinder 35. Pressure fluid may be introduced to the cylinder 36 through the bore 39 in the converter casing 13. Admission of pressure fluid to the cylinder 36 will move the piston 31 rearwardly so as to engage the torque converter lock-up clutch C and directly connect the driving shaft 3 to the intermediate solid shaft 30. On release of the pressure fluid from cylinder 36 suitable spring means (not shown) and the force of the pressure fluid within converter casing [3 will urge the piston 31 forwardly to disengage the clutch C and provide a means for the transmission of a troque multiplying drive from shaft 8 through the fluid operated torque converter A and the associated hollow intermediate shaft iii.

The gear box B includes the planetary gear trains 50, 60, which provide means for the transmission of torque multiplying reverse and forward drives respectively. The gear box housing 42 includes the forward wall portion 421?. to which is connected by bolt means 43 a radially extending flange 32d of the axially extending hollow a certain speed. Consequently, pump .84 provides pressure fluid for operation of the transmission unit during a pushed or towed start even if engine driven pump 25 is inoperative due to a dead engine or the like. Suitable controls such as the arrangement shown in Figs. 4 and 5 and subsequently described in detail, are provided to insure that pump 84 automatically takes over the supply of pressure fluid for the transmission unit whenever the speed of output shaft 81 exceeds a certain predetermined value. This relieves the transmission driving engine of the load of front pump 25 after the engine unit has begun to drive the transmission output shaft 8!.

Also drivingly mounted on the output shaft 8! (see Figs. 3, 4 and 5) is a speed responsive, centrifugal force operated governor mechanism 85 which provides one of the means for automatically controlling operation of this transmission unit. It is obvious that various types of speed and torque responsive controls may be used with this transmission but the specific governor mechanism 85 herein disclosed is particularly advantageous due to its simplified design and novel manner of operation. This governor unit is arranged such that it does not require shaft driven gearing or electrically operated control units but instead uses hydraulic pressure supplied by the rear pump 84 in combination with the centrifugal force effect of a pair of output shaft mounted weights 88, 89 for controlling actuation of the radially movable governor control valve 95 so as to provide a novel type of governor mechanism.

The governor 85 comprises the body portion 86 having a cylindrical bore 81 extending inwardly from one end thereof. Reciprocably'mounted in the bore 81 are the cylindrical primary and secondary weights 88 and 89 respectively, which weights are telescopically arranged for movement relative to each other. Extending between the spaced apart flanges on the weights 88 and 89 is a preloaded compression spring 90 that tends to urge the weights 8% and 89 apart. A snap ring 9| mounted in the bore 81 of valve body 86 provides a seat for the primary weight 88 when it is moved outwardly a predetermined distance by centrifugal force due to the rotation of driven output shaft 8 I. Mounted in the bore in primary weight 88 is a snap ring 92 that provides a seat for the secondary weight 89 on the primary weight 88. Extending through aligned bores in the secondary weight 89 and the driven output shaft 8! is a tie shaft 94 that has one end suitably anchored to the secondary weight 89 by means of a snap ring or the like. The other end of tie shaft 99 has mounted thereon the piston type governor control valve 95. The governor valve 95 is arranged to reciprocate in the T- shaped bore 96 in the valve body 86. Governor piston valve 95 has spaced lands 95a and 950 of different diameters connected by a narrow neck portion 95b. Extending through the valve body 86 transversely to bore 96 and intersecting bore 96 are the pressure fluid inlet and outlet passages 91 and 98 respectively. Passage 9'! is arranged to be connected by conduit means (see Figs. 4 and 5) to the outlet from rear oil pump 84. The pressure fluid from pump 84 is thus applied through inlet passage 91 to the stem portion of valve bore 96. The outlet passage 98 from the stem portion of the piston bore 96 is connected to an outlet conduit I03. The conduit I83 conducts the pressure fluid discharged from the piston valve bore 96 to the cylinder .14 I d (see Figs. 4-. and 5) in which is mounted the pilot valve I45 of the automatic control valve unit 0. 5 Control valve unit H9 is subsequently described in detail. Valve body 86 also includes a relief port Ifll to relieve the excess pressure of the fluid in bore 96 of the governor unit 85. Relief port {0| also acts as a means to balance the valve 95 in the bore 96 when it is acted on by the weights 88, 89 and the pressure fluid in bore 96. Thevalve body 86 is fixedly connected to the driven output shaft 8i by the set screw I00. The governor tie shaft 94 is of such size as to be freely slidable in its shaft receiving bore through output shaft 8| and is not required to serve as a means for fastening the governor body 86 to the output shaft 8|.

The governor 85, which functions as afluid' pressure reducing valve, receives fluid under pressure from the rear pump 84 as soon as output shaft 8| begins to rotate. This pressure fluid from pump 84 is admitted to the valve bore 96 through the inlet passage 91 and a hydraulic pressure is applied to the opposed inner surfaces of valve lands 95a and 950. As land 950 is larger in diameter than land 95a there is an unbalanced area which causes an unbalanced-force to be applied to piston valve 95 which force tends to move valve 95 radially outward so as to cause valve land 95a to close off the pressure fluid inlet passage 91. Due to the rotation of output shaft 8| there is also a simultaneously actin centrifugal force tending to urge the primary and secondary weights 88, 89 radially outward. As tie shaft 94 connects weights '88 and 89 to piston valve 95 it is obvious that the centrifugal force of the weights 88 and 89 and their connecting spring 96 is opposed by the hydraulic pressure applied to the unbalanced area of the piston valve land 95c. Consequently the centrifugal force of the elements 88, 89, 99 tends to move valve 95 so as to uncover the passage 91 and connect the pressure fluid inlet passage 91 to the valve bore 96 and outlet passage 98 while the unbalanced hydraulic force applied to piston valve land 95c tends to shift valve 95 in the opposite radial direction so as to close off the connection between 192181 passage 91 and the valve bore 96 and outlet The pressure fluid that is admitted to valve bore 96 is conducted through the outlet passage 98 to other parts of the control system to actuate the various control devices that will be subsequently described in detail.

If the pressure of the fluid admitted to the bore 96 from inlet 91 becomes excessive and exceeds the centrifugal force of the elements 88, 89, then valve will move radially outward a sufficient amount to uncover the relief port I8! and the pressure fluid in the stem portion of bore 96 will spill out and reduce the pressure of the contamed fluid to a value where a condition of equilibrium will again be set up between the centrifugal force of the elements 88, 89, 90 and the unbalanced force applied to the valve land 950. A more complete description of the operation of this governor device 85 is set forth in the previously referred to co-pending application of William L. Sheppard, Serial No. 98,493.

While the pressure of the fluid discharged from the pump 84 into the governor inlet passage 91 is almost constant and also greater than the pressure of the fluid discharged from the governor valve bore 96 into the outlet passage 98, due to the reducing valve action of piston valve 95, still, it is thought to be obvious that the pressure of the fluid discharged from the governor 85 is roughly proportional to or responsive to'the speed of the output shaft 81 and that governor :85 pro vides an efficient, simplified form .of speed sensitive .control mechanism.

Cooperating with the speed sensitive governor 35 to control operation of this transmission is a torque regulating or responsive control means I253. The torque regulating control means I20 (see Figs. 4 and that is operably associated with this transmission comprises the kiekdown valve I2I and the throttle valve I23. This control means I2!) is operated by the conventional throttle control or accelerator pedal H5 for the engine unit (not shown) that drives the transmission unit. Pedal I I5 is connected to the kick- .down valve I2! by the linkage IIB. Kickdo-w-n valve I2I is arranged to reciprocate in the valve cylinder body I22 and is connected to the reciprocably mounted throttle valve I23 by a preloaded compression spring I24. At the closed throttle position of the accelerator pedal I-I5 with the manually operated drive ratio control valve I'iil set for drive (see Fig. 5) the arrangement is such as to pressurize conduits I25 and I28 with pump pressure fluid. Admission of pump pressure fluid to conduit I28 applies pressure fluid to the chamber 692) on the apply side of servo 69 and causes application of brake band .82 to drum member 64a to condition the transmission for the accelerating, torque multiplying underdri-ve. Clutch C is disengaged at this time for the positions of throttle valve I23 and shift valve i 50 at closed throttle are such as to prevent pressure fluid from conduit I25 from entering conduits I55 and 155a to effect engagement of clutch C. At closed throttle the land I-23a of I throttle valve I23 is positioned so as to substantially close cylinder port 122a and prevent the pump pressure fluid or so-called line pressure fluid (approximately 90 p. s. i.) in supply conduit I25 from being transmitted to chamber I221) of the valve cylinder I22. At closed throttle there is suificient preload on spring I24 to shift valve I23 to the left a sufiicient amount to permit seepage of a certain amount of pressure fluid from conduit I25 around valve land 123a into chamber 1221; to develop about 20 p. s. i. pressure in chamber I22!) and in conduit I21 at closed throttle. Land I23a does not however prevent the line pressure fluidin conduit I'2-5 from passing through the cylinder by-pass groove I-22d and entering the'conduit I 26 that communicates with the line pressure inlet port I4Ia in one end of the cylinder body I ii of the automatic controlvalve mechanism I40. As the accelerator pedal -I- I5 depressed from its closed throttle position-to initiate vehicle acceleration the kickdown valve 121 is moved to the left and this movement is transmitted by spring 124 to throttle va-lve I23 which latter valve is moved to the left a sufficient amount to uncover the line pressure inlet port 122a in cylinder body I22 and admit line pressure fluid from conduit I25 to the chamber I221) of the cylinder I22. The line pressure admitted to chamber i221) from inlet port I220; at partial depression of the accelerator pedal I I5 is of a lower pressure than the line pressure in conduit I25 due to the reducing valve action of the throttle valve I23. The pressure of the fluid admitted to the chamber I221) by the reducing valve action of throttle valve I23 is hereafter referred to as throttle controlled pressure and the pressure of this pressure fluid varies with degree of throttle opening. At wide open throttle with pedal I115 substantially depressed there is substantially a direct connection between conduit I 25 and cham- 7 her I22b. Consequently, the throttle controlled pressure :inchamber I22b will equal the line pressure in conduit I 25. The admission of throttle controlled pressure fluid tochamber I 22b of cylinder J22 has a tendency to shift the throttle valve I23 to the right to oppose depression of the ac?- .celerator .pedal for it Will'be noted than an axially extending bore I23d through the throttle valve I-2.3 applies the throttle controlled pressure fluid in chamber I22b to the bor 122k at .the left end .of valve 423 which throttle controlled pressure reacts against the -'left end .of throttle valve .123 and tends to balance the force .of the pressure besing applied .to the right end .of valve 423 "by the accelerator pedal actuated kickdown valve .;I2.I through the compressed spring I24. The bore structure 123d thus cooperates with the cylinder i22lt at the left end .of throttle valve I23 and provides a pressure fluid regulator .control for governing the pressure and the volume of the throttle controlled pressure fluid introduced into the chamber 1.221), the conduit I27, and the asso, .ciated chamber I4-Ib of automatic control valve 140.

The throttle controlled pressure admitted to valve chamber 14th of automatic control valve unit J40 during initialdepression of the accelerator pedal M5, when valve I10 is set for drivef applies a variable pressure to the leftend of iand Idea of shift valve I50 (see Fig. 5) which pressure assists the spring I5I in urging shift valve 158 towards the right end of valve cylinder I4I which is the downshifted position of the valve 150. Thus during initial depression of accelerator pedal H5 the valve land a of shift valve 150 is positioned so that it covers line pressure inlet port Lilla .to the valve cylinder I41 and prevents line pressure from supply conduit I26 from passing into the chamber I 4=Ic of valve cylinder I44. Thechamber I4Ic is connected by conduits 1I;5;5 and I55a with the control cylinder '36 of the torque converter lock-up clutch C and by QOnduits I55 .and I55?) with the release side 69a of the servo .69 .of the for-ward drive planetary gear train .60. Thus it will be seen that the .posi- :tion of shift valve :I5Ii control engagement and disengagement of the direct drive or converter lock-up :clutch C as well as disengagement of the braking band '62 of the forward drive planetary gearing 60. It is therefor thought to be Obvious that the position of shift valve land 150a flontrols the automatic upshifts and downshifts between the accelerating underdri-ve ratio trans- ..mitted through the series arranged torque converter A and the forward drive planetary gearing .50 and the cruising directdrive ratio transmitted through engaged clutch C and the solid shaft 30.

"As the accelerator pedal II-5 is further depressedduring initiation .of normal forward start- 111g drive through the series arranged torque con verter A and forward drive gear train 60, the .speed vof driven tailshaft IlI is increased and consequently the governor pressure, that is the Pressure :of the output shaft speed responsive fluid directed from the governor outlet =98 through conduit L013 :to the chamber I 4-Id of the auto- ;matic control valve unit Mil, is gradually increased. The governor pressure directed into chamber I4Id of valve unit I 40 {see Fig. 4) is applied to the right end or head use of the pilot valve I45 which valve :is reciprocably mounted in the valve cylinder I II. This variable governor pressure applied to the pilot valve I45 tends'to shift-the pilot valve towards the left. Movement of pilot valve I45 to the left is opposed by the vari- 1 I able throttle controlled pressure fluid in chamber I4I b at the opposite end of valve cylinder I4I which latter pressure is urging the shift valve I50 towards the right. The shift valve I50 is directly engaged to the pilot valve I45 through the stem portion I501).

As the speed of output shaft 8i increases the governor pressure applied to the chamber I4Icl and to the right end or head I45d of pilot valve I45 increases in intensity and creates a force that gradually overcomes the force of the throttle controlled pressure in valve chamber (4i?) at the left end of cylinder I4I. When the force resulting from the governor pressure in chamber I4Id exceeds the force exerted by the throttle controlled pressure in chamber hill) and that of the spring Ii then the pilot valve I45 shifts towards the left and moves the shift valve I50 to the left at the same time. As soon as the land I45a of pilot valve I45 has been moved sufficiently to the left to uncover the throttle controlled pressure inlet port I lie in cylinder I41 then throttle controlled pressure from conduit I5! is admitted to the bore portion I4Ig of the cylinder I4I. Admission of throttle controlled pressure fluid to the bore portion I4Ig of valve cylinder I4I fills connected conduits i58 and I59 and lag pressure chamber I4Ij of cylinder I4I with throttle controlled pressure fluid. Admission of throttle controlled pressure fiuid to the lag pressure chamber I4If of valve body I4I applies a leftwardly directed force to the lag area I501) at the right end of the shift valve I50. This leftwardly directed, throttle controlled pressure generated force applied to the shift valve I50 combines with the governor pressure force applied to the head I45d of pilot valve I45 to overcome the rightwardly directed throttle controlled pressure generated force that is being applied to the left end of land [50a of the shift valve I50. As a result of the sudden rearrangement of the several forces applied to the shift valve I50, due to the admission of throttle controlled pressure to the lag pressure chamber I4If, the shift Valve I50 is suddenly shifted or snapped towards the left and the line pressure inlet port I4Ia is connected to the chamber I4 Ic of valve body I4I so that line pressure from conduit I26 is now admitted to the conduit I55 and directed by branch conduit 55a (see Figs. 4 and 5) into the cylinder 30 of lockup clutch C to cause engagement of the clutch C.

At the same time line pressure from conduit E55 will be directed by branch conduit I551) into chamber 69a on the release side of servo 69 to effect disengagement of the brake band 52. The

transmission unit has thus been automatically upshifted from the condition whereby it transmits the torque multiplying, accelerating underdrive ratio to the condition whereby it transmits .a direct drive as a result of the coordinated action of the hydraulic governor 85, the torque regulating control unit I20, and the automatic change speed control valve unit I40.

While most upshifts and downshifts of the there are times when it is advantageous to have a manually controlled means to overrule the automatic control valve unit I40 in order toeffect a kickdown or downshift from direct drive to the accelerating underdrive ratio when operating at "a speed above that at which the automatic downshift would occur. Such a manually controlled 12 kickdown means is included in this control system. To effect such a kickdown it is merely necessary to depress the accelerator pedal II5 to its wideopen throttle position and this will shift the valve land I2I'b (see Fig. 4) of kickdown valve I2I to the left a suificient amount to connect conduit I59 with the chamber I22g of valve cylinder I2I and with kickdown pressure relief valve I29. Connection of conduit I59 with valve I29 reduces the pressure in the lag pressure chamber I4If of valve cylinder MI to the pressure setting of relief valve I29 (12 p. s. i.) This venting of the throttle controlled pressure from the lag pressure chamber 54h through relief valve I29 reduces the forces holding the shift valve I50 in its upshifted position and conditions the automatic control valve unit I40 for a downshift provided the throttle controlled pressure in chamber I4Ib is sufficient to overrule the governor pressure in chamber I4 Id. When the kickdown valve I2I is depressed to its wide open throttle position to accomplish a kickdown it will be noted that the valve land I2Ic of valve I2I will block off the inlet port I22) from conduit I58. This closes the passageway connecting conduit I58 with conduit I59 through the valve cylinder I22. Valve land I2 Ic thus prevents flow of throttle controlled pressure fluid from conduit I50 to conduit I59 through the aforementioned passageway in the valve cylinder I22. To insure a suflicient supply of throttle controlled pressure fluid to the conduit I59 and lag chamber I4If during kickdown so as to maintain a reduced pressure in conduit I59 of approximately the setting of kickdown relief valve I29 (12 p. s. i.) the conduits I50 and I59 are connected by a small bleed bore I220. Bore I220 permits a small amount of throttle controlled pressure fluid in conduit I58 to bleed into the conduit I59 so as to pressurize conduit I59 and compensate for leakage and at the same time maintain sufficient throttle controlled pressure in the conduit I58 and the automatic control valve unit I40 to insure proper functioning of the valve unit I20. Loss of throttle controlled pressure in the valve unit I40 due to a venting of conduit I58 through relief valve I29 might prevent a downshift of shift valve I50 due to insufficient throttle controlled pressure in chamber Hill) to overrule the governor pressure in chamber I-IId.

With the throttle controlled pressure in chamber I4I reduced to 12 p. s. i. due to the kickdown valve I2I venting the lag chamber I4If through the relief valve I29, conditions are such that the throttle controlled pressure in chamber I4Ib may then overcome the force of the governor pressure in chamber Mid and the shift valve I50 will shift towards the right to complete the kickdown to the condition for transmitting the underdrive ratio. It is obvious that at a very high vehicle speed the governor pressure in chamber I4Id may be so great that the throttle controlled pressure in chamber I4Ib can not overcome the effect of the governor pressure in chamber I4Id and then a kickdown is impossible. The automatic control valve unit I40 thus provides an upper limit kickdown level which prevents kickdown at very high speeds. This prevents damage to the transmission and insures smooth transmission performance. It will be noted that the diameter of the pilot valve I is greater than the diameter of shift valve I therefore with substantially equal throttle controlled and governor controlled pressures, such as may exist at high vehiclespeeds, a downshift 1 3 will not ibe accomplished due to the greater force efiect of the governor pressure in chamber Mild holding the shift valve 159 in upshifted position. For a more detailed explanation of the transmission control system .see .the aforementioned application of William L. Sheppard, ,Serial ,No. 98,493, filed June 11, 1949.

The control system shown in :Figs. 4 and :5 also includes the conduits 1-81 and I 82 which connect the pumps 25 and M respectively with a pressure regulator valve unit I85. Spring 1 86 :of pressure regulator valve I85 determines the pressure that is to be maintained in the line pressure fluid supply conduit 'I9I that connects regulator valve I85 to the manual control valve unit 165. A pressure of approximately .90 p. .s. i. in :conduit I19I has been found to be satisfactory for operation of this transmission control system in the drive and coast ratios whereas a pressure :of approximately 180 p. s. i. is used for reverse. Pressure regulator valve I85 provides each of these pressures in a manner that is subsequently explained. The pump output conduits I91 and I 82 each include check valves I93 and. I84 respectively to insure a suitable pressure head in the control system at all times. With the control arrangement shown the pump 25 supplies the fluid pressure for starting drive under ordinary conditions and as the speed of output shaft "BI increases the pump 8'4 automatically takes over and feeds the manual "control valve supply conduit I9I. As pump 84 comes into operation the pressure fluid supplied therefrom is transmitted by conduit -'I82a to chamber IBIa of pressure regulator valve body -I-8-I and this pump pressure acts on piston valve I88 and moves valve I88 towards the left compressing spring I86. Movement of valve I88 to the left displaces this valve sufficiently so as to connect conduit I8I through branch conduit IBM to by-pass conduit I99 thereby providing a bypass "for the output of the front pump 25. Upon the operation of either pump 25 or '84 the fluid pressure in conduit ISZa is transmitted to the chamber IB-Ib of valve body "I81 through bore I' 88a in valve I88. The pressure in chamber I8-I'a is always sufiicient 'to'move valve I88 slightly to the left so as to connect conduit 182a with conduit I92 which supplies pressure fluid to the torque converter unit A. This arrangement maintains the converter unit A full of fluid during all operations thereof. Restriction I93 in conduit I92 controls the volume of the fluid supplied to the converter .A. The fluid directed through the converter A is returned to the supply sump 26 through the conduit I94 that is connected 'to suitable pressure fluid cooling means I95. 'Condu'it I96 leading from the cooling means I95 is connected to a valve unit I9! that includes the pressure relief valve I98 for controlling the pressure of the fluid supplied to the converter unit A. This converter pressure control valve I98 maintains a pressure of about 40 pounds per square inch in the converter unit A. Valve 'unit I91 (see Fig. 4) "also includes a bypass conduit I910 that connects the pressure fluid passed through valve I98 to a pressurized lubrication system that is controlled .by the pressure control valve I99. Valve I99 maintains apressure .head inthe lubrication system and dumps the excess pressure fluid supplied thereto into the supply sump "2B. Conduit 290 connects the valve 99 of valve unit I97 to the supply sump 26.

The manual controls for this transmission unit (see Fig. 5) includes the :drive selector lever ;I:IsI which is rotatably mounted pn the conven- .tional vehicle steering column I ,:I 2. Control lever I :I I is connected to the manually operated control valve I10 of valve .unit I 65 by-the linkage arrangement I13. Drive selector lever I11 I has four positions as .clearly shown in Fig. .5. These positions include reverse; neutral, drive .and coast .or'manually controlled vkickdovvn. The four positions are-denoted by the letters R, N, D and C respectively in .the various figures .of the drawings.

Operation plies pressure :fluid to the reverse drive servo .59.

Accordingly, none of the planetary brake bands 52, :62 nor the direct clutch C will be engaged and neither a forward nor reverse drive is transmittable to the output shaft :BI. The front pump .at this time will merely circulate fluid through the converter A and the lubrication system while the rear pump '84 is inactive.

if the drive selector .lever H1 is moved to the forward drive position (as shown in Fig. 15) valve land I'IIia of manual control valve I 1.9 will be positioned to the right of outlet .port Illa so that pressure fluidfromsupply conduit I'9I passes through the manually operated control valveassembly I-"Hl .and into the control conduits 125, I.2:6,,and I28. It will be noted that the line pres- .sure fluid .in conduit I251-is conducted by branch conduit I28 to the apply or on side 6% of servo (59 :so as to activate the planetary gearing '69 for transmission of the starting forward underdrive. As reverse drive supply conduit 202 and coast drive supply conduit 293 are both blocked oif from the line pressure supply conduit I9: by the lands use and HM respectively of control valve I10, when control valve I it is positioned for drive, obviously reverse planetary will not beactivated and the shift valve I50 will not be locked in its downshifted coast position so as to prevent the automatic upshift to direct drive when the speed and torque conditions for accomplishing such an upshift are attained.

Prior to depression of the accelerator pedal I I5 from its closed throttle position, when drive selector lever I I I is positioned in drive, the throttle valve I23 and the shift valve IEIl will be so positioned in their respective valve cylinders that sufiicient pressure fluid from conduits I 25 and 128, will not be introduced into either of these control valve mechanisms nor into the conduit 55, I551]. to cause engagement of direct drive or torque converter lock-up clutch C. Furthermore, the engine speed at closed throttle with the transmission set in the forward drive position will be such that slip in the torque converter unit A and drag of the associated drive train elements will prevent a forward drive being transmitted .to the driven shaft :81 even though the planetary brake band 62 is applied to activate the forward drive planetary gear train 60.

Subsequently, as the accelerator pedal H5 ,is depressed to increase the speed of the driving engine unit (not shown) and to initiate forward movement of the vehicle, the throttle valve I23 will be moved towards the left in the manner previously described and :suflicient \thI'OttlG controlled pressure fluid from valve chamber I22b of the accelerator responsive valve unit I will be admitted to the control conduit I21, and to the chamber I4 I b of the automatic control valve unit I so as to condition the control system for the automatic upshift to direct drive. During initial depression of the accelerator pedal [IS the force 'of the throttle controlled pressure on the left end .of land Ia of shift valve I50 is greater than the force of the governorpressure in chamber I4ld that is transmitted to the right end of shift valve I50 by the pilot valve assembly. Accordingly, the shift valve I50 will be urged towards the right and positioned so that land [50a blocks off the line pressure inlet port I0 Ia from the conduit I26 and consequently line pressure fluid cannot be introduced into conduits I55, Ia and I55b to eifect engagement of the direct drive clutch C and disengagement of brake band 62 of the planetary gearing which gearing is arranged for the transmission of the starting forward drive. Accordingly, during initial forward acceleration in the drive ratio the relatively high torque multiplication of the converter unit A is combined with the torque multiplication effect of the planetary gearing 60 to provide an efiicient, highly effective torque multiplying underdrive. This drive is from drive shaft 6 through converter A to turbine driven intermediate driven shaft I6 and then through planetary gearing 60 to the output shaft 8|.

On continued depression of the accelerator I I5 and increase in the output shaft speed there occurs the previously described automatic upshift to direct drive. As the speed of output shaft 8| increases, and the torque load decreases, the speed responsive governor pressure in chamber llld of the automatic control valve I40 will increase and overrule the throttle controlled pressure in chamber I4Ib of the control valve unit whereupon shift valve I50 will be shifted towards the left to connect conduits I26, I55, I55a and I551) to effect engagement of the direct clutch C and disengagement of brake band 62. This shift of valve I50 to the left converts the accelerating relatively high torque multiplying underdrive into a positively connected, efiicient direct drive for cruising purposes.

On upshift of valve I50 line pressure fluid is admitted to the conduit I55 from conduit I26 through valve unit I40. This line pressure fluid is conducted to the direct drive or lock-up clutch C and to the release side of servo 69. Admission of pressure fluid to clutch C locks up the torque converter and conditions the transmission for the transmission of the cruising direct drive. Pressure fluid admitted to conduit I55 is also transmitted by conduit I 55b to the release or off side of servo 69 to effect disengagement of the planetary brake band 62 and thereby terminate the accelerating torque multiplying underdrive.

It is thought to be obvious that the automatic upshifts and downshifts will occur at varying speeds depending on the relationship existing between the governor controlled pressure and the throttle controlled pressure under varying conditions. At light or closed throttle when the torque requirement is relatively low the upshift will occur at about 18 miles per hour whereas at wide open throttle with a relatively high torque load the upshift may not occur until at about 60 miles per hour vehicle speed. The automatic downshifts will vary with the speed and torque relationships but, as previously pointed out, the downshift for a given speed and torque condition ISO drive into a direct drive.

'16 will be at a lower vehicle speed than the corresponding upshift due to the effect of the lag pressure in valve chamber I4If of the control valve I40. The automatic downshifts will preferably occur between 10 and 15 miles per hour vehicle speed and must be at a speed less than the closed throttle automatic upshift so as to prevent hunting of the shift valve.

If, While traveling in the cruising direct drive ratio, a high speed accelerating underdrive is desired, then a kickdown to a more favorable accelerating ratio may be manually effected by merely depressing the accelerator pedal II5 to its wide open throttle position and thereafter kickdown valve I2I will effect the kickdown or downshift in the manner previously described.

It will be noted that whenever the transmission is set for drive that the throttle controlled pressure in branch conduit I2'Ia is conducted to the apply or on side of servo 69. Thus the force applying the band 62 is always directly proportional to the throttle controlled pressure. This is quite advantageous as it tends to smooth out the application of the band 62 and to also reduce slip of the band during the upshifts and downshifts.

In addition to the automatic downshift from direct drive to the accelerating underdrive, which downshift is primarily controlled by the speed responsive governor 85, and the manually effected kickdown from direct drive, which is accomplished by maximum depression of the foot accelerator II5, there is still a third way in which to effect a downshift from direct drive to the accelcrating underdrive ratio with this transmission control system. This transmission control system includes a shift lever setting for obtaining a coast drive ratio wherein the accelerating underdrive ratio used for starting forward drive is used for coast braking. The coast drive setting provides a means for downshifting valve I50 and directs the line pressure fluid into chamber I4Ik of the automatic control valve cylinder I4 I. Line pressure in chamber Mlle will prevent the governor pressure in chamber I4 I d from shifting the pilot valve assembly I45 to the left so as to upshift the shift valve I50 and convert the under- It will be noted that when the manual control valve I10 has been shifted to the coast drive position so as to locate land I 10a on valve I'I0 adjacent the right edge of the outlet I IIc to conduit 203 that then line pressure fluid is also being admitted to the drive control conduit I25. As previously pointed out the admission of pressure fluid to conduit I25 will apply the forward drive brake band 62 and condition the transmission for the torque multiplying underdrive.

Reverse drive may be obtained by moving the drive selector lever I I I to the reverse control position. This positions the manually operated control valve I10 in such a position that the valve land I: of valve I10 is adjacent the right edge of the line pressure inlet port I'IIb and the land I'I0b adjacent the left edge of the outlet port I'IIe so that pressure fluid from supply conduit I9I is directed into the outlet port I'IIe at the left end 17 of valve body Ill and into the reverse servo control conduit 202. At this time all forward drive control conduits are blocked off from line pressure supply conduit I9I by valve land Illla. The forward drive control conduits I25 and 203 at this time are opened to the sump 26 through the drain I'II g at the right end of valve body "I so as to drain the pressure fluid from both the direct drive clutch D and the forward drive servo control unit 69. Admission of pressure fluid to the reverse control conduit 2B2 actuates the reverse band servo 59 and applies reverse braking band 52 so that the planetary gearing 50 will transmit a reverse drive from input shaft 8 and turbine driven shaft I5 through planetary gearing 50 to output shaft 8|. It will be noted that with the manual control valve I10 positioned for reverse drive that line pressure fluid from supply conduit I9I will not be directed through conduit 205 into the chamber I8lc of the pressure regulator valve body I87 therefore the pressure regulator valve I85 will function in such a manner as to cause an increased pressure (180 p. s. i.) to be applied to the reverse band servo 59 instead of the 90 p. s. i. used for application of forward servo 69. The increased pressure in servo 59 is necessary to take the higher torque reaction applied to the band 52 as a result of the gear ratio of the reverse planetary 50. The operation of the pressure regulator valve I85 is fully explained in the aforementioned William L. Sheppard application, Serial No. 98,493.

In addition to providing a gear ratio for coast braking this transmission unit includes mechanism such that either of two forms of turbobraking may be brought into operation to assist the engine braking that may be obtained when the transmission unit is conditioned for the transmission of direct drive. From Fig, 6 it will be noted that a manually operable control lever 22I may be operated by suitable control linkage 222 in such a manner that the beam lever 223 may be rocked about its fulcrum point 224. Movement of lever 22I towards the left'will rock beam 223 into engagement with and cause actuation of the brake band applying mechanism 225 of reverse drive servo 59. Actuation of mechanism 225 will apply the brake band 52 to reverse drive planetary gearing 56 at a time when the transmission unit is transmitting a forward direct drive through the engaged clutch C and intermediate solid shaft 30. Application of brake band 52 at a time when the clutch C is engaged for the transmission of a forward direct drive causes the converter turbine member I5 to be driven in a reverse direction from the direction of rotation of the converter impeller member I4 and energy is accordingly dissipated in the converter unit A in a manner that effectively brakes the speed of the impeller I3 and the output shaft SI. If a less effective turbo-brake is required then lever 22I may be rocked to the right to cause beam lever 223 to engage and actuate the brake band'applying mechanism 225 of the forward drive servo 69 so as to apply the brake band 62 to the forward drive planetary gearing 60. Application of band 62 at a time when the transmission unit is transmitting direct drive through the engaged clutch C will drive the converter turbine member I5 forwardly at a different rate of speed than the speed of the converter impeller member I4 and therefore energy will be dissipated in the converter unit A and the output shaft 8| will be braked. Obviously the brake provided by application of the forward drive brake band 62 is not as effective as that provided by the application of the reverse drive brake band 52 for the relative directions of rotation of the impeller I4, and the turbine I5 are not opposed to one another when band 62 is applied whereas application of band 52 during forward direct drive produces opposed rotation of members I4 and I5. While manually operated mechanical mean 22I226 are shown in Fig. 6 for operation of the servos 59 and 69 to accomplish th turbo braking, it is considered within the scope of this invention to substitute pneumatic, hydraulic or similarly operated mechanisms for the linkage means 22 I-226.

It is thought to be obvious from the foregoing description that there is provided an improved,

highly flexible, simplified type of motor vehicle power transmission unit that provides all the necessary gear ratios and control features for maximum performance and driving comfort and yet permits manufacture and assembly at an said annulus gear, drive transmitting means connecting said planet pinion carrier to said output shaft, brake means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, underdrive to said output shaft, a clutch means adapted to be connected between said input and output shafts to provide means for the transmission of a positive, direct drive therebetween, and differential pressure fluid operated control means operatively associated with said brake means and said clutch means to automatically and alternately apply and release the said brake and clutch means to thereby automatically effect the transitions between underdrive and direct drive, said'control means including a source of pressure fluid responsive to the speed of the output shaft, a source 3 of pressure fluid responsive to the opening of the .engine throttle and a differential pressure operated valve connected to said sources of variable pressure and actuable by the pressure differential therebetween to automatically operate said clutch and brake means.

2. In an engine driven motor vehicle drive train including an engine throttle control and a power transmission unit drivingly connected to the engine comprising, an input'shaft, an output shaft, a hydraulic torque converter unit mounted therebetween comprising operatively associated impeller, turbine and reaction wheels, means drivingly connecting said input shaft and said impeller wheel, a planetary gear train, comprising an annulus gear, a sun gear and a planet pinion carrier mounting planet pinion gears, interposed between said converter unit and said output shaft, means drivingly connecting said turbine wheel to said annulus gear, drive transmitting means'connecting said planet pinion carrier to saidoutput shaft, brake means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, underdrive from said input to said output shaft, a clutch means adapted to be connected between said input and output shafts to provide means for the transmission of a positive, direct drive therebetween, control means operatively associated with said brake means and said clutch means to automatically andalternately apply and release the said brake and clutch means to thereby effect the automatic transitions between underdrive and direct drive, said automatically operable control means including a source of pressure fluid responsive to the speed of the vehicle, pressure fluid operated means responsive to the movement of the engine throttle, and a differential pressure operated valve connected to said brake and clutch means and to said sources of pressure fluid and adapted to be operated by the pressure differential therebetween to accomplish the automatic transitions between underdrive and direct drive.

3. In a drive train including an engine driven power transmission unit and an enginethrottle control, an engine driven. input shaft, an output shaft, a hydraulic torque converter unit mounted therebetween comprising operatively associated impeller, turbine and reaction Wheels, means drivingly connecting said input shaft-and said impeller wheel, a'planetary gear train, comprising an annulus gear, a sun gear and a planet pinion carrier mounting planet pinion gears, interposed betweensaid converter unit and said output shaft, means drivingly-connecting said turbine wheel to said amiulusgear, drive transmitting means connecting said planet pinion carrier to said output shaft, brake means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, underdrive to said output shaft, a clutch means adapted to be connected between said input and output shafts to provide means for the transmission of a positive, direct drive therebetween, pressure fluid operated control means operatively connected with said brake means and said clutch means to automatically and alternately apply and release thesaid brake and clutch means to thereby automatically effeet the transitions between underdrive and direct drive, said control means including a source of pressure fluid responsive to the speed of the output shaft, 9. source of pressure fluid responsive to the opening of the engine throttle and a differential pressure operated'valve connected to said sources of variable pressure and actuable by the pressure differential therebetween to automatically operate said clutch and brake means, and manually operable pressure fluid control means connectible with said differential pressure operated valve adapted to overrule the automaticallyoperable control means and actuate said brake and clutch means to effect "a downshift from direct drive to the torque multiplying underdrive at thewill of the operator.

'4. In a drive train including an engine driven power transmission unit and an engine throttle control, an input shaft drivingly connected to said engine, an output shaft, a hydraulic torque converter unitmounted therebetween comprising operatively associated impeller, turbine and reaction wheels, means drivingly connecting said input shaft and said impeller wheel, a planetary gear train, comprising an annulus gear, a sun gear and a planet pinion carrier mounting planet pinion gears, interposed between said converter unit and said out-put shaft, means drivingly connecting said turbine wheel to said annulus gear, drive transmitting means connecting said planet pinion carrier to said output shaft, brake means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, underdrive to said output shaft, a clutch means adapted to be connected between said input and output shafts to provide means for the transmission of a positive, direct drive therebetween, pressure fluid operated control means operatively associated with said brake means and said clutch means to automatically and alternately apply and release the said brake and clutch means to thereby automatically effect the transitions between underdrive and direct drive, said control means including a source of pressure fluid responsive to the speed of the output shaft, a source of pressure fluid responsive to the opening of the engine throttle and a differential pressure operated valve connected to said sources of variable pressure and actuable by the pressure differential therebetween to automatically operate said clutch and brake means, a first manually'operable pressure fluid control means connectible with said differential pressure operated valve adapted to overrule the automatically operable control means-to provide for continuous operation of the transmission unit in the underdrive ratio regardless of the speed of the output shaft and the throttle opening, and a'sec- 0nd manually operable control means associated with'the said brake means adapted to engage said brake means when said transmission unit is transmitting direct drive to thereby provide a turbo-brake efiect in said converter for the output shaft.

5. In a drive train for a motor vehicle having an engine, an engine throttle control and a drive selector lever,'a power transmission unit including an engine driven input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels,'means drivingly connecting said input shaft'and said impeller wheel, a planetary gear train, comprising an annulus gear, a sun gear and a planet pinion carrier mounting planet pinion gears, interposed between said converter unit andsaid output'shaft, means drivingly conmeeting said turbine Wheel to said annulus gear, drive transmitting means connecting said planet pinion carrier to said output shaft, brake means adapted to anchor said sun gear against rotation so as-to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, forward, underdrive from said inputshaft to-said output shaft, a clutch means within said converter unit adapted to connectsaid input and output shafts for the transmission of a positive, forward, direct drive, auto matically operable pressure fluid operated control meansadapted to operate said brake and clutch means to effect automatic upshifting from said underdrive to said direct drive, and to automatically downshift said direct drive to said underdrive, said automatically operable control means including a source of pressure fluid responsive to the speed of the vehicle, pressure fluid operated means responsive to the movement of the engine throttle, and a differential pressure operated valve connected to said brake and clutch means and to said sources of pressure fluid and adapted to be operated by the pressure differential therebetween to accomplish the automatic transitions between underdrive and direct drive, engine throttle actuated pressure fluid operated control means to manually overrule said automatically operable control means and eifect a downshift from the direct drive ratio to the underdrive ratio at the will of the operator, and drive selector lever actuated pressure fluid operated control means to manually effect a downshift from the direct drive ratio to the underdrive ratio.

6. In a drive train for a motor vehicle having an engine, an engine throttle control and a drive selector lever, a power transmission unit including an engine driven input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivingly connecting said input shaft and said impeller wheel, a planetary gear train, comprising an annulus gear, a sun gear and a planet pinion carrier mounting planet pinion gears, interposed between said converter unit and said output shaft, means drivingly connecting said turbine wheel to said annulus gear, drive transmitting means connecting said planet pinion carrier to said output shaft, brake means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, forward, underdrive from said input shaft to said output shaft, a clutch means within said converter unit adapted to connect said input and output shafts for the transmission of a positive, forward, direct drive, automatically operable pressure fluid operated control means adapted to operate said brake and clutch means to effect automatic upshifting from said underdrive to said direct drive, and to automatically downshift said direct drive to said underdrive, said automatically operable control means including a source of pressure fluid responsive to the speed of the vehicle, pressure fluid operated means responsive to the movement of the engine throttle, and a difierential pressure operated valve connected to said brake and clutch means and to said sources of pressure fluid and adapted to be operated by the pressure differential therebetween to accomplish the automatic transitions between underdrive and direct drive, engine throttle movement actuated, pressure fluid operated control means to manually overrule said automatically operable control means and effect a downshift from the direct drive ratio to the underdrive ratio at the will of the operator, drive selector lever actuated, pressure fluid operated control means to manually effect a downshift from the direct drive ratio to the underdrive ratio. and additional manually operable control means to apply the brake means while the clutch means is transmitting a direct drive between said input and output shafts to thereby provide for converter turbo-braking of the output shaft.

7. In a motor vehicle drive train including an engine, an engine throttle control and a power transmission unit driven by the engine comprising, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, I

means drivingly connecting said input shaft and said impeller wheel, first and second planetary gear trains, each'comprising operatively asso-' ciated annulus, sun and planet pinion gears and a planet pinion gear carrier, interposed between said converter unit and said output shaft, drive transmitting means connecting said turbine wheel to the annulus gear of said first planetary gear train and to the sun gear of said second planetary gear train, drive transmitting means connecting the planet pinion carrier of said first planetary gear train and the annulus gear of said second planetary gear train to said output shaft,

brake means adapted to anchor the sun gear of said first planetary gear train against rotation so as to provide means for transmitting a combination hydraulically and mechanically transmitted, forward, underdrive from said input shaft to said output shaft, brake means adapted to anchor the planet pinion carrier of said second planetary gear train against rotation so as to provide means for the transmission of a combination hydraulically and mechanically transmitted reverse drive from said input shaft to said output shaft, a clutch means adapted to connect said input and output shafts for the transmission of a positive, forward, direct drive, and pressure fluid operated automatically operable control means associated with the brake means of said first planetary gear train and said clutch means to provide means for the initiation of all forward drive through said underdrive after which automatic upshifts to direct drive and automatic downshifts from direct drive will be automatically accomplished in accordance with the variations in speed of said output shaft and the movement of the engine throttle control, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to the speed of the output shaft, a second variable pressure fluid wherein the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a differential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure diiferential between said first and second pressure fluids whereby the third pressure fluid is applied to th controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive.

8. In a drive train, an engine, an engine throttle control and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivingly connecting said input shaft and said impeller wheel, first and second planetary gear trains, each comprising operatively associated annulus, sun and planet pinion gears and a planet pinion gear carrier, interposed between said converter unit' and said output shaft, drive transmitting means pinion carrier of said first planetary gear train and the annulus gear of said second planetary gear train to said output shaft, brake means adapted to anchor thesun gear of said first planetary gear train against rotation so as to -provide means for transmitting a combination hydraulically and mechanically transmitted, forward, .underdrive from said input shaft to'said output shaft, brake means adaptedcto anchor the planet pinion carrier of said second planetary'gear train against rotation so as to provide means for the transmission of a combination hydraulically and mechanically transmitted reverse drive from said input shaft to said output shaft, a clutchmeans adapted to connect, said input and output shafts for the transmission of a positive, forward, direct drive, and pressure actuated automatically operable control means associated with the brake means of said first'planetary gear train and said clutchv means liQplICWidG' means for the initiation of all forward drive through said underdrive after which automatic upshifts to direct drive and automatic downshifts from direct drive will be accomplished in accordance with variations in the speed of said output shaft and the movement of the engine throttle control, said automatically operable pressure fiuid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to'the speed of the output shaft, a second variable pressure fluid wherein the pressure is'responsive to the degree of engine throttle opening, 'athird pressure fluid of substantially constantxpressure, and a diiferential pressure operated control valve connected to, said threepressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluids whereby the thirdpressure hold is applied to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive and manually operablecontrol means to effect application ofv said brake means for said first or second planetary gear trains while direct drive is being transmitted such that a turbo-brake for said output shaft is obtainable.

9. in a drive train, an engine, an engine throttle control and an engine driven powertransmission unit comprising, an input shaft, an output shaft, a hydrodynamic coupling including impeller, turbine and reaction elements interposed between said input and output shafts, said impeller element being drivingly connected to said input shaft, a first intermediate hollow shaft drivingly connected to said turbine element, a second intermediate shaft arrangedconcentrioally within and rotatable relative to said first intermediate shaft, a clutch means having engageable driving and driven elements carried by saidinput shaft and said second intermediate shaft respectively, a forward drive planetary gear train comprising a sun gear, brake means therefore, an annulus gear, planet pinion gearing, and a carrier for the planet'pinion gearing, means drivingly connecting the first intermediate shaft tozthe annulus gear of the'forward drive gear train, means drivingly connecting the planet pinion carrier of the forward drive gear train to the second intermediate shaft, means drivingly connecting the second intermediate shaft to the output shaft and pressure fluid operated automatically operable controlmeans to alternately'apply the brake means for the forward drive planetary sun gear and toefiect engagementof the clutch 'means, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to the speed of the output shaft, a second variable pressure fluid wherein-the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a differential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluids whereby the third pressure fluid is applied to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive.

10. In a drive train, an engine, an engine throt tle control and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydrodynamic coupling includingimpel-ler, turbine and reaction elements interposed between said input and output shafts, said impeller element being drivingly connected to said input shaft, a first intermediate hollow shaft drivingly connected to said turbine element, a second intermediate shaft arranged concentrically within and rotatable relative to said first intermediate shaft, a clutch means having engageable driving and driven elements carried by said input shaft and said second intermediate shaft respectively, a forward drive planetary gear train comprising a sun gear, brake means therefore, an annulus gear, planet pinion gearing, and a carrier for the planet pinion gearing, means drivingly connecting the first intermediate shaft. to the annulus gear of the forward drive gear train, -means drivingly connecting the planet pinion carrier of the forward drive gear train to the second intermediate shaft, means drivingly connecting the second intermediate shaft to the output shaft and pressure fluid operated automatically operable control means to alternately apply the brake meansfor the forward drive planetary sun gear, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to the speed of the output shaft, a second variable pressure fluid wherein the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a differential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluids whereby the third pressure fluid is applied to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio, drive and to effect engagement of the clutch means, and manually operable control means to overrule said auto-v matically operable control means to simultaneously effect-disengagement of the clutch means and engagement of the brake means for the forward drive gear train to establish drive through an underdrive ratio at times when the automatically operable control means would normally establish direct drive.

11. In a drive train, an engine, an engine throttle control, and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydrodynamic coupling including impeller, turbine and reaction elements interposed between said input and output shafts, said impeller element being drivingly connected to said input shaft, a first intermediate hollow shaft drivingly connected to said turbine element, a second intermediate shaft arranged concentrically within and rotatable relative to said first intermediate shaft, a clutch means having engageable driving and driven elements carried by said input shaft and said second intermediate shaft respectively, a forward drive planetary gear train comprising a sun gear, brake means therefore, an annulus gear, planet pinion gearing, and a carrier for the planet pinion gearing, means drivingly connecting the first intermediate shaft to the annulus gear of the forward drive gear train, means drivingly connecting the planet pinion carrier of the forward drive gear train to the second intermediate shaft, means drivingly connecting the second intermediate shaft to the output shaft and pressure fluid operated automatically operable control means to alternately apply the brake means for the forward drive planetary sun gear and to effect engagement of the clutch means, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to thespeed of the output shaft, a second variable pressure fluid wherein the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a differential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluids whereby the third pressure fluid is applied to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive, and manually operable control means to apply the brake band for the sun gear of the forward drive planetary gear train while the clutch means is engaged to provide a converter generated turbo brake for direct drive.

12. In a drive train, an engine, an engine throttle control, and an engine driven transmission unit, comprising, an input shaft, an output shaft, a hydrodynamic coupling including impeller, turbine and reaction elements interposed between said input and output shaft, said impeller element being drivingly connected to said input shaft, a first intermediate hollow shaft drivingly connected to said turbine element, a second intermediate shaft arranged concentrically within and rotatable relative to said first intermediate shaft, a clutch means having engageable driving and driven elements carried by said input shaft and said second intermediate shaft respectively, a forward drive planetary gear -train comprising a sun gear, brake means therefore adapted to anchor same against rotation in at least one direction, an annulus gear, planet pinion gearing, and a carrier for the planet pinion gearin means drivingly connecting the first intermediate shaft to the annulus gear of the forward drive gear train, means drivingly connecting the planet pinion carrier of the forward drive gear train to the second intermediate shaft, means drivingly connecting the second intermediate shaft to the output shaft, a reverse drive planetary gear train comprising a sun gear, an annulus gear, planet pinion gearing and a carrier for the planet pinion gearing, means drivingly connecting the first intermediate shaft to the sun gear of the reverse drive gear train, means drivingly connecting the annulus gear of the reverse drive gear train to the planet pinion carrier of the forward drive gear train, brake means adapted to be applied to the planet pinion carrier of the reverse drive gear train to anchor same against rotation in at least one direction and pressure fluid operated automatically operable control means to alternately apply the brake means for the forward drive planetary sun gear and to effect engagement of the clutch means, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to the speed of the output shaft, a second variable pressure fluid wherein the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a differential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluid whereby the third pressure fluid is applied to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive.

13. In a drive train, an engine, an engine throttle control, and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydrodynamic coupling including impeller, turbine and reaction elements interposed between said input and output shafts, said impeller element being drivingly connected to said input shaft, a first intermediate shaft drivingly connected to said turbine element, a second intermediate shaft arranged concentrically around and rotatable relative to said first intermediate shaft, a clutch means having engageable driving and driven elements carried by said input shaft and said second intermediate shaft respectively, a first planetary gear train comprising a sun gear, an annulus gear, planet pinion gearing, and a carrier for the planet pinion gearing, means drivingly connecting the first intermediate shaft to the annulus gear, means drivingly connecting the planet pinion carrier to the second intermediate shaft, means drivingly connecting the second intermediate shaft to the output shaft, and brake means adapted to be applied to the sun gear of the forward drive gear train to anchor same against rotation in at least one direction, a source of constant intensity line pressure fluid, a source of variable pressure fluid responsive to the speed of the output shaft, a source of variable pressure fluid responsive to the engine throttle opening, and a differential pressure operated control valve connected to said sources of pressure fluid and to said clutch and brake means to automatically and alternately apply the brake means and the clutch means, and manually operable control means to effect disengagement of said clutch means and application of said brake means irrespective of the speed of the output shaft and the condition of the engine throttle.

14. In a drive train, an engine, an engine throttle control and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivingly connecting said input shaft and said impeller wheel, first and second planetary gear trains, each comprising operatively associated annulus, sun and planet pinion gears and a planet pinion gear carrier, interposed between said converter unit and said output shaft, drive transmitting means connecting said turbine wheel to said first planetary gear train and said second planetary gear train, drive transmitting means connecting said first planetary gear train and said second planetary gear train to said output shaft, brake means adapted to be applied to said first planetary gear train so 27 as to provide means for transmitting a combination hydraulically and mechanically transmitted, forward, underdrive from said input shaft to said output shaft, brake means adapted to be applied to said second planetary gear train so as to provide means for the transmission of a combination hydraulically and mechanically transmitted reverse drive from said input shaft to said output shaft, a clutch means adapted to connect said input and output shafts for the transmission of a forward, direct drive, pressure fluid operated automatically operable control means associated with the brake means of said first planetary gear train andsaid clutch means to provide means for the initiation of all forward drive through said underdrive after which automatic upshifts to direct drive and automatic downshifts from direct drive will be accomplished in accordance with the variations in speed of said output shaft and the movement of the engine throttle control, said automatically operable pressure fluid operated control means comprising a first variable pressure fluid wherein the pressure is responsive to the speed of the output shaft, a second variable pressure fluid wherein the pressure is responsive to the degree of engine throttle opening, a third pressure fluid of substantially constant pressure, and a diiferential pressure operated control valve connected to said three pressure fluids and arranged to be operated by the pressure differential between said first and second pressure fluids to direct the third pressure fluid to the controls for said clutch and the brake means for said first planetary gear train to accomplish automatic changes in speed ratio drive, and manually actuated, pressure fluid operable control means adapted to overrule said automatically operable control means by effecting actuation of said brake means of said first planetary gear train and said clutch means so as to provide means for the d'own'shifting of said direct drive to said underdrive at the will of the operator.-

15. In a drive train, an engine, an engine throttle control and an engine driven power transmission unit comprising, an input shaft, an output shaft, a hydraulic torque converter unit mounted the're'between comprising operatively associated impeller, turbine and reaction wheels, means 'drivingly connecting said input shaft and said'impeller wheel, a planetary gear train, cornprising an annulus gear, a sungear anda planet pinion carrier mounting planet pinion gears, operatively connected and interposed between said converter unit and said output shaft, means drivingly connecting said turbine wheel to said 28 gear train, drive transmitting means connecting said gear train to said output shaft, brake means adapted to be applied to said gear train so as to activate said gear train and provide means for the transmission of a combination hydraulically and mechanically transmitted, torque multiplying, underdrive from said input shaft to said *output shaft, a clutch means adapted to be connected between said input and output shafts to provide means for the transmission of a direct drive therebetween, pressure fluid operated control means operatively associated with said brake means and said clutch means to automatically and alternately apply and release the said brake and clutch means to thereby effect the transitions between underdrive and direct drive, said automatically operable control means including a source of pressure fluid responsive to the speed of the output shaft, a source of pressure fluid operated means responsive to the movement of the engine throttle, and a difierential pressure operated valve connected by pressure fluid means to said brake and clutch means and to each of said sources of pressure fluid and arranged to be operated by the pressure differential resulting from the simultaneous application of pressurized fluid from each of said pressure fluid sources to opposed portions of said valve to automatically effect speed ratio changes between the aforementioned underdrive and direct drive.

JOSEPH JANDASEK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,088,782 Ford et a1 Aug. 3, 1937 2,102,634 Lysholm Dec. 21, 1937 2,120,104 Livermore June '7, 1938 2,229,337 Neracher et al Jan. 21, 1941 2,302,714 Pollard Nov. 24, 1942 2,329,724 Maurer Sept. 21, 1943 2,368,684 Simpson Feb. 6, 1945 2,418,378 Voytech Apr. 1, 1947 2,433,052 Kelley Dec. 23, 19 17 2,456,328 Schneider Dec. 14, 1948 2,478,868 Hasbany Aug. 9', 1949 2,516,208 Hasbany July 25, 1950 2,518,825 Simpson Aug. 15, 1950 2,519,050 Kelbel Aug. 15, 1950 FOREIGN PATENTS Number Country Date 267,079 Great Britain Feb. 18, 1932 

